CODEWITHSUNDEEP
sql-server
Rajesh
Rajesh

Reputation: 6589

Get substring in SQL Server

I want to get a substring in SQL Server from last sequence of a split on dot (.).

I have a column which contains file names such as hello.exe, and I want to find the extension of the file exactly as Path.GetExtension("filename") does in C#.

Upvotes: 18

Views: 32107

Answers (5)

Michael Fayad
Michael Fayad

Reputation: 1336

The following SQL request adressed most of the edge cases in my weird database where many files didn't have extensions.

select distinct reverse(left(reverse(fileNameWithExtension), charindex('.', reverse(fileNameWithExtension)) - 1))
from myTable
where charindex('.', reverse(fileNameWithExtension)) - 1 > 0 and charindex('.', reverse(fileNameWithExtension)) - 1 < 7 and fileNameWithExtension is not null

Upvotes: 0

Sylvain Rodrigue
Sylvain Rodrigue

Reputation: 4994

Same as accepted answer, but I've added a condition to avoid error when filename is null or when filename has no extension (no point):

select
    reverse(substring(reverse(filename), 1, 
        charindex('.', reverse(filename))-1)) as FileExt
from
    mytable
where 
    filename is not null
and charindex('.',filename) > 0

Upvotes: 1

Hss
Hss

Reputation: 21

Try this

SELECT RIGHT(
             'C:\SomeRandomFile\Filename.dat',
             CHARINDEX(
                       '.',
                       REVERSE(
                               'C:\SomeRandomFile\Filename.dat'
                              ),
                       0)
              -1)

Upvotes: 2

Eric
Eric

Reputation: 95243

You can use reverse along with substring and charindex to get what you're looking for:

select
    reverse(substring(reverse(filename), 1, 
        charindex('.', reverse(filename))-1)) as FileExt
from
    mytable

This holds up, even if you have multiple . in your file (e.g.-hello.world.exe will return exe).

So I was playing around a bit with this, and this is another way (only one call to reverse):

select 
    SUBSTRING(filename, 
        LEN(filename)-(CHARINDEX('.', reverse(filename))-2), 8000) as FileExt
from
    mytable

This calculates 10,000,000 rows in 25 seconds versus 29 seconds for the former method.

Upvotes: 30

marc_s
marc_s

Reputation: 755531

DECLARE @originalstring VARCHAR(100)
SET @originalstring = 'hello.exe'

DECLARE @extension VARCHAR(50)

SET @extension = SUBSTRING(@originalstring, CHARINDEX('.', @originalstring) + 1, 999)

SELECT @extension

That should do it, I hope! This works as long as you only have a single '.' in your file name - separating the file name from the extension.

Marc

Upvotes: 2

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